Abstract: An improved plasma torch nozzle which has a substantially barrel shaped body having a longitudinal opening therethrough for directing the flow of gas for a plasma arc from rearward portions of the body downstream to forward portions of the body and then out of a face at the forward portions to form a plasma arc in the presence of a sufficient electrical potential difference. The nozzle body particularly comprises a rear section for which the outer surface portions diverge with respect to the downstream direction, a center section for which the outer surface portions are cylindrical with respect to the downstream direction, and a forward section for which the outer surface portions converge with respect to the downstream direction so that the respective outer surface portions form a continuous outer surface for the nozzle body that encourages the flow of gases that is directed along the outer surface of the nozzle body to follow the outer surface and converge at the face of the nozzle body.

Abstract: A nozzle for use with a plasma arc torch having a first gas flow within the nozzle for engaging an electrode and generating a plasma and a second gas flow in surrounding engagement to the outer surface of the nozzle is disclosed. The nozzle includes an outer surface of substantially hourglass configuration in longitudinal cross-section so that the second gas remains in close contact with the outer hourglass surface of the nozzle to provide efficient heat transfer from the nozzle to the surrounding second gas flow.